Leonardo remembers the night he met Ayrton Senna, 10 years ago this week. Brazil's footballers were in Paris to play a friendly match at the Parc des Princes as part of their preparation for that summer's World Cup in the USA. A cheerful and relaxed Senna, wearing a grey sweater and black trousers, received an ovation from the hundreds of flag-waving Brazilians in the crowd as he kicked off the match before retreating to the grandstand.

"It was the year he hoped to become world champion for the fourth time," Leonardo said in Italy this week, "and it was the same with our team. 'This is our year,' he told us." Within a fortnight Senna was lying on the track at Imola, mortally wounded. And three months later, when the footballers won their fourth title in Pasadena, they gathered in the centre of the pitch and held up a banner bearing his name.

This week, a few days before the race that will mark the 10th anniversary of Senna's death, most of the 1994 Brazil squad pulled on the gold-and-green shirts again in commemoration of their compatriot. At the little ground in Forli, a few miles from Imola, they played a match against the formula one drivers' team. All 7,000 grandstand seats were sold and hundreds of local children were allowed to sit on the banked cycle track encircling the pitch as Leonardo, Dunga, Claudio Taffarel, Jorginho, Aldair and the rest took on Michael Schumacher, Rubens Barrichello, Fernando Alonso, Jarno Trulli and others.

"Senna was very, very important to Brazilians, and he still is," Leonardo said, hoisting his small daughter on to his shoulders as he left the pitch wearing Barrichello's black-and-white chequered shirt. "We remember the way he carried our flag around the track every time he won a race. And when I was introduced to him that night, I felt like I was meeting someone I already knew very well."

But Senna's appeal radiated far beyond Brazil, and Wednesday's match was a prelude to a weekend in which he has once again become the most talked-about figure in formula one. Ten years after his death, his absence has never been more obvious.

In the short term, his death exerted an extraordinary effect on the sport's popularity. As if sucked into the vacuum, new adherents quadrupled the TV audience over the next eight years, stirred by the reminder that grand prix racing is a world in which the young and glamorous deliberately court danger. Now, after the recent downturn, a troubled sport prays for the emergence of someone with his combination of aggression and refinement, of brutality and subtlety, of ego-driven ambition and an almost feline grace.

Michael Schumacher is certainly not the answer, for all his record-setting six championships (to Senna's three) and 73 grand prix victories (to Senna's 41). By comparison, the German is a two-dimensional figure whose ruthlessness and supreme skill are not accompanied by a sense of intellectual or spiritual quest. This weekend, too, Schumacher is a somewhat equivocal figure, since it was he, at the wheel of a car long suspected of benefitting from illegal driver aids, who was hounding Senna when the Brazilian lost control at 190mph.

"It was my first experience of death in the sport I most love," Schumacher said on Thursday, careful also to acknowledge the accident, the day before Senna's, that took the life of the Austrian driver Roland Ratzenberger. "At least we have seen a lot of action in terms of safety happening since that day. It doesn't really justify it, but at least we can see something positive out of it."

Up and down the Imola paddock the famous figures of today and yesterday - including those, such as Juan Pablo Montoya and Fernando Alonso, to whom he was a boyhood hero - are being asked questions about the meaning of Senna's life and death. About why, in fact, Ayrton Senna still matters so much, and why a man who habitually bullied opponents out of the way and was not above double-crossing his own team-mates has been transformed into a figure of almost angelic innocence.

Arguments still rage, not least over the cause of the fatal crash. Damon Hill, Senna's team-mate, expressing his opinion on the subject for the first time outside a courtroom, blames a driver error. Jo Ramirez, for many years Senna's best friend in the paddock, calls that "the biggest bullshit I've ever read". Bernie Ecclestone suggests that if he had lived, all those race wins and titles would not have one Schumacher's way. Meanwhile workmen are ordered to obliterate a message painted by fans earlier this week on the fatal wall at Tamburello, reading " Ayrton sempre numero 1, il piu grande " - Ayrton always No1, the greatest - because it might distract the drivers in tomorrow's race.

Yesterday the only sign of Senna's posthumous presence at the reshaped Tamburello was the statue unveiled several years ago opposite the location of the accident, surrounded by fresh floral tributes. Elsewhere the business of keeping his memory alive is in full swing, not least on the bodywork of the Jordan and Minardi cars, which are carrying his picture and the Brazilian flag. Proceeds from the football match, a genial 5-5 draw, will go to various charities including the Senna Foundation, which in the years since the driver's death has raised and spent around £250m, helping almost four million Brazilian children via a series of social and educational programmes.

Viviane Senna, his older sister, created the foundation after Ayrton's death at the age of 34 as a way of carrying his memory into a new century and furthering his humanitarian ambitions. "He didn't have time to do it himself," she said before kicking off the match in Forli, "but he left a seed in our hearts. At a certain point in his life he came to the conclusion that winning wasn't so important when compared with the poverty and injustice suffered by millions of people in Brazil. Ayrton had a strong character, and not only in the car."

Senna's qualities outside the cockpit lent another dimension to his appeal, with the result that no racing driver in history has been more thoroughly celebrated in death. Some of those who were killed in the days when grand prix racing still took a regular toll of human life, notably Jim Clark and Gilles Villeneuve, were commemorated for years after their death, but none of them gripped the worldwide imagination as Senna did. Fans flocked to adore a four-wheeled gladiator who studied the Bible and spoke of mystical experiences in the cockpit.

"It was through his values that Ayrton showed us a lot of things," Leonardo said as drivers and footballers mingled on their way back to the dressing room in Forli. "And when he died, we understood what his life had meant."

Jo Ramirez, McLaren's team co-ordinator during the years when Senna won his titles in the red-and-white cars, returned to the Imola paddock this week to speak of his friend's aura. "It wasn't just his personality. It was something he had earned. There was respect around him. He had a big heart."

To set against the charisma, the patriotism, the good works and the Bible-study, however, are vivid memories of the Senna who turned formula one into a contact sport by driving his rivals off the track and who liked to stack the odds in his favour. "He wasn't a saint," Ramirez concluded. "He had his moods. Sometimes his values weren't the same as other people's. He used to say to me, 'Nice men don't win grands prix.'"

Nice or not, something about Senna drew people to grand prix racing. Yesterday, as his undistracted successors bounced across the kerbs of the fiddly chicane that replaced the Tamburello curve after his death, engines popping and banging as the electronic traction control cut in, formula one looked and sounded more than ever like a cruel parody of itself.

On the inside of the concrete wall near the place where he died, behind a row of saplings and recently installed wire fencing, loving messages from his fans are slowly fading with the years. But the memory of Senna remains in sharp focus, a reminder of a time when Michael Schumacher could be beaten and grand prix racing still seemed larger than life.